General Description
The MAX887 high-efficiency, step-down DC-DC converter provides an adjustable output from 1.25V to 10.5V. It accepts inputs from 3.5V to 11V and delivers 600mA. Operation to 100% duty cycle minimizes dropout voltage (300mV typ at 500mA). Synchronous rectification reduces output rectifier losses, resulting in efficiency as high as 95%.
Fixed-frequency pulse-width modulation (PWM) reduces noise in sensitive communications applications. Using a high-frequency internal oscillator allows tiny surface-mount components to reduce PC board area, and eliminates audio-frequency interference. A SYNC input allows synchronization to an external clock to avoid interference with sensitive RF and data acquisition circuits.

FEATUREs
♦ 95% Efficiency
♦ 600mA Output Current
♦ Cycle-by-Cycle Current Limiting
♦ Low-Dropout, 100% Duty-Cycle Operation, 300mV at 500mA
♦ Internal 0.6Ω (typ) MOSFET
♦ Internal Synchronous Rectifier
♦ High-Frequency Current-Mode PWM
♦ External SYNC or Internal 300kHz Oscillator
♦ Guaranteed 260kHz to 340kHz Internal Oscillator Frequency Limits
♦ 2.5µA Shutdown Mode

APPLICATIONs
  Portable Instruments
  Cellular Phones and Radios
  Personal Communicators
  Distributed Power Systems
  Computer Peripherals